A833 od 4 speed abuse

I think if you treat it as a "3 speed with a cruising gear" you will be OK.

I guess you realize that "4th" gear is REALLY "3rd" gear, so in the OD gear you are putting stress on the just about everything--the gear on the rear of the clutch pinion, the cluster, and the side forces on the mainshaft caused by the travel through the cluster to "3rd" gear.

While shifting up through the gears does the same thing, here you are causing this stress for miles and miles and miles.

Also, in OK, there is an RPM difference between the input pinion and the mainshaft, so there's more stress on those bearings.